Induced Earthquakes

Evidence is mounting that seismicity in many locations in the central U.S. is induced by the deep injection of fluids from nearby oil and gas operations. Learn more about our current understanding of human-caused earthquakes.

Overview

The number of earthquakes in the central United has increased dramatically over
the past decade. Between the years 1973–2008, there was an average of 25
earthquakes of magnitude three and larger in the central and eastern United
States. Since 2009, the average number of M3 earthquakes has jumped to 362 per
year. The rate peaked in 2015 with 1010 M3+ earthquakes. Since 2015 the
earthquake rate has declined, with 690 and 364 M3+ earthquakes in 2016 and 2017,
respectively. Nonetheless, this rate is far higher than the average of 25
earthquakes per year. Most of these earthquakes are in the magnitude 3–4
range—large enough to have been felt by many people—yet small
enough to rarely cause damage. Damage has been caused by some of the larger
events, including the M5.8 Pawnee and M5.0 Cushing Oklahoma earthquakes that
occurred in 2016.

This increase in earthquakes prompts two important questions:

Are they natural, or man-made?

What should be done in the future as we address the causes and consequences of these events to reduce associated risks?

Increasing Rate of Earthquakes Beginning in 2009

Annual number of earthquakes with a magnitude of 3.0 or larger in the central and eastern United States, 1970–2016. The long-term rate of approximately 25 earthquakes per year increased sharply starting around 2009.